1. Field of the Invention
This invention relates generally to stoppers and seals used for access and vent holes in a container, and more specifically to an improved stopper apparatus for use with wine barrels and the like, providing a positive seal fermentation lock for the barrel.
2. Description of the Prior Art
Wine barrels and related containers typically include a bung hole or vent hole in a side or end of the barrel, through which the barrel can be filled or emptied, and the contents of the barrel accessed for topping off, testing, sampling, treatment and the like. The bung hole is usually sealed with a frusto-conically shaped stopper member to prevent contaminants from entering the barrel, and to prevent air circulation into or out of the barrel. These stopper members are often made from wood, rubber, silicone, or like material, and are well known and in widespread use. Carbon dioxide and/or other gasses may be produced as a byproduct of the wine fermentation process. These gasses may accumulate in the barrel until the gas pressure exceeds the sealing pressure provided by the stopper, at which time the stopper is displaced and the gas escapes. Often, displacement of the stopper is a minor matter and of little consequence, such that the stopper continues to provide a zero-pressure seal. However, on other occasions the displacement may be significant, resulting in a complete loss of sealing.
A solution to this problem is disclosed in U.S. Pat. No. 5,702,018, to Montgomery (the instant inventor), which teaches a positive seal fermentation stopper apparatus for wine barrels or vent holes in any vessel. The disclosed apparatus includes a generally frusto-conical stopper member having a top surface, a bottom surface, and an outer circumferential surface which is adapted to seal against the inner circumferential surface of a barrel""s bung (vent) hole, all in the traditional manner. The stopper member includes a central aperture having a length and a diameter, preferably along the longitudinal axis of the stopper member. The apparatus further includes a sealing insert member having a top portion, a middle portion, and a bottom portion, with the top portion having a diameter greater than the stopper member central aperture, and which has a lower surface adapted for sealing engagement against the stopper member top surface. In the preferred embodiment, the top portion lower sealing surface is conical in shape to provide an efficient sealing geometry with the stopper member (preferably flat) top surface. The sealing insert member middle portion has a length generally equal to the stopper member central aperture, and a diameter less than the stopper member central aperture, and is thus adapted for passage therethrough. The sealing insert member terminates in a bottom portion which includes at least one, and preferably two or more preferably opposed flexible lateral projection elements adapted to contact and apply a force against the stopper member bottom surface, so as to urge the top portion lower surface into sealing engagement with the stopper member top surface.
This arrangement thus seals the bung hole or vent hole to provide a positive seal against air or any other matter entering the barrel. When gases form inside the vessel or wine barrel, the resultant pressure will exert a force against the insert member top portion lower sealing surface, and flex the lateral projection elements, breaking the seal formed between the insert member top portion lower sealing surface and the stopper member top surface, thus allowing the gas to escape. The amount of pressure required to operate this one-way valve can be adjusted by appropriate selection of the size and position of the lateral projection elements, or by changing the properties of the materials used.
Although the stopper apparatus of the ""018 patent provides a solution to the problem of maintaining an air tight seal while simultaneously allowing trapped gases to escape from a fermentation vessel, it must still be replaced when the fermentation process is complete and barrel aging is commenced. This requires the purchase and use of a second set of stoppers, at considerable expense. Additionally, the removal of the positive seal fermentation lock exposes the liquid contents inside the barrel to atmospheric mircoorganisms and other contaminants, which, while incidental in degree may nonetheless imperil the quality of the production.
Accordingly, it would be desirable to provide a stopper apparatus which could function as both a gas-releasing positive seal fermentation lock and a permanent barrel bung for use during barrel aging or storage.
The positive seal fermentation lock for wine barrels of the present invention provides an improvement over the stopper apparatus disclosed and taught in the ""018 patent. As with the stopper apparatus disclosed in the ""018 patent, the fermentation lock of the present invention comprises a generally frusto-conical stopper member having a top surface, a bottom surface, and an outer circumferential surface which is adapted to seal against the inner circumferential surface of a barrel""s bung (vent) hole, all in the traditional manner. Furthermore, the stopper member includes a central aperture having a length and a diameter, preferably along the longitudinal axis of the stopper member.
The apparatus also includes a sealing insert member having a top portion, a middle portion, and a bottom portion, and it is preferably fabricated from a deformable material, such as neoprene rubber, natural rubber, silicone rubber, nitrile rubber, EPDM rubber, urethane rubber, and any thermosets or thermoplastic elastomers. However, whereas the top portion of the insert member as described and taught in the ""018 patent is substantially larger than the diameter of the central aperture of the stopper member, the deformable and compressible top portion of the improved apparatus of the present invention has a diameter only slightly greater than the stopper member central aperture, and thus may be pushed into the central aperture so that the top surface of the sealing insert member is flush with the top surface of the stopper member. The sealing insert member further has a lower surface adapted for sealing engagement against the stopper member top surface. In each of the preferred embodiments, the top portion lower sealing surface is conical in shape to provide an efficient sealing geometry with the stopper member (preferably flat) top surface. In a first preferred embodiment, the sealing insert member middle portion has a length generally equal to the stopper member central aperture, and a diameter less than the stopper member central aperture, and is thus adapted for passage therethrough. The sealing insert member terminates in a bottom portion which includes at least one, and preferably two or more preferably opposed flexible lateral projection elements adapted to contact and apply a force against the stopper member bottom surface, so as to urge the top portion lower surface into sealing engagement with the stopper member top surface. In a second preferred embodiment of the improved stopper apparatus, the central portion of the bottom surface of the stopper member includes a cylindrical recess (circular in cross section) and has a recessed depth sufficient to accommodate the flexible lateral projection elements. In this instance, the central aperture of the stopper member terminates at its lower end in the recess so that the middle portion of the sealing member insert member is of a shorter length than in the first preferred embodiment.
The stopper apparatus of the present invention seals a bung or vent hole to provide a positive seal against air or any other matter entering the barrel. When gases form inside the vessel or wine barrel, the resultant pressure will exert a force against the insert member top portion lower sealing surface, and flex the lateral projection elements, breaking the seal formed between the insert member top portion lower sealing surface and the stopper member top surface, thus allowing the gas to escape. The amount of pressure required to operate this one-way valve can be adjusted by appropriate selection of the size and position of the lateral projection elements, or by altering the properties of the materials used.
When gas production from within the barrel is complete and/or when barrel aging or storage is commenced, the sealing insert member may simply be pushed down into the central aperture of the stopper member so that the top surface of the insert member is flush with the top surface of the stopper member, at which time (while inserted in a barrel bung hole) it will be virtually indistinguishable in appearance from a conventional bung.